The invention relates to a device and method for flushing out contaminants from a fluid line. The invention is particularly applicable for flushing out a water supply line, such as used in water irrigation systems, and is therefore described below with respect to this application, but it will be appreciated that the invention could advantageously be used in other applications.
It has been found desirable to flush out water irrigation lines at the start and finish of each irrigation cycle in order to remove sedimentation and other contaminants accumulating in the line between irrigation cycles when no water is flowing through the line. One technique presently used includes a line flushing valve which is normally open to discharge the contaminants when the pressurized water is first applied to the line to flush out the contaminants, and then automatically closes after a predetermined time delay determined by a labyrinth through which the water flows. However, in such a system, it frequently happens that the closing of the valve is delayed, or even prevented, by clogging of the valve, thereby not only producing a large wastage of water, but also requiring manual intervention to close the valve and to clean it of the clogging particles.